Biodiversity is the variation in living organisms, viewed within a given habitat, ecosystem or in the world as a whole. The concept is usually applied to the species diversity, although the notion of genetic biodiversity is applied to the variation in genes within an individual species. While most people think of rainforests as loci of great biodiversity, biomes such as oceans and grasslands are the likely repositories for even greater variation. Retention of diverse biota is important, since intact ecosystems are thought to be essential for provision of ecosystem services to humans, including maintenance of a diverse foodbank, pollination, clean water, flood control, pest control, waste decomposition, biomass energy resources and climate stability. Biodiversity is presently critical since we live in the era of the Mass Holocene Extinction, a period of species loss caused by man, and unrivaled in rate of species loss. Although the number of total species numbers in the tens of millions, most have not yet even been described. The extinction of a species is almost always related to destruction of habitat or man-made pollution.
The Permian period lasted from 290 to 248 million years ago and was the last period of the Paleozoic Era. The distinction between the Paleozoic and the Mesozoic is made at the...
East African halophyticsLast Updated on 2014-12-22 14:42:45
WWF Terrestrial Ecoregions Collection
The East African Halophytics ecoregion is composed of two hypersaline lakes situated within Tanzania, along the Great Rift Valley. These lakes constitute an inhospitable environment for most plants and animals, since the waters are saline, elevated in temperature, and subject to rapid salinity changes following rains. In fact, Lake Natron, exhibits one of the highest salinities of any lacustrine body on Earth, attaining super-saturated salt levels of 340 parts per thousand.
However, the lakes are home to huge flocks of lesser and greater flamingos that breed on the mudflats which surround the lakes. The lesser flamingos filter the blue-green algae from the salty waters, and the greater flamingos feed on copepod larvae within the shallow lake waters. The East African Halophytics habitat is threatened by active... More »
Species diversityLast Updated on 2014-12-07 19:11:57
Species diversity is a measure of the diversity within an ecological community that incorporates both species richness (the number of species in a community) and the evenness of species' abundances. Species diversity is one component of the concept of biodiversity.
Species diversity is influenced by species richness. All else being equal, communities with more species are considered to be more diverse. For example, a community containing 10 species would be more diverse than a community with 5 species.
Species diversity is also influenced by the relative abundance of individuals in the species found in a community. Evenness measures the variation in the abundance of... More »
OverfishingLast Updated on 2014-12-07 17:22:32Overfishing is the human act of extracting aquatic (that is, marine and freshwater) fauna from natural water bodies at a rate greater than the reproductive and recruitment functions can replace that extraction. While there is some evidence that localized overfishing may have occurred in prehistoric eras, the bulk of overfishing has taken place in the last 150 years as the human population has expanded greatly and fishing technologies have enabled harvesting of many species at rates not imagined in earlier times. For over a century man's role in the depletion of certain regional fisheries has been noted. A functional definition of overfishing is sometimes given as the reduction in catch per unit effort by fishermen. Typically the concept of overfishing is linked to an individual aquatic species, and this issue is most often discussed within a specific marine or lacustrine province... More »
BiomeLast Updated on 2014-11-30 22:01:13Biomes organize the biological communities of the earth based on similarities in the dominant vegetation, climate, geographic location, and other characteristics. Aspects of the physical environment such as precipitation, temperature, and water depth, have a strong influence on the traits of species living in that natural environment, and thus biological communities experiencing similar environmental conditions often contain species that have evolved similar characteristics. There is no single classification of biomes that is agreed upon by all scientists because different scientists wish to emphasize different characteristics by their definition. Historically however, biomes have been identified and mapped based on general differences in vegetation type associated with regional variations in climate and terrain.
Terrestrial biomes characterize ecosystems on land, and are usually... More »
Alberta Mountain forestsLast Updated on 2014-11-30 21:48:14
WWF Terrestrial Ecoregions Collection
The Alberta Mountain forests ecoregion lies entirely within Canada and almost fully within the province of Alberta, but hugs the Alberta-British Columbia border from Banff northward to Jasper and Kakwa. The ecoregion is classified within the Temperate Coniferous Forests biome.
Mean annual temperature in the Eastern Continental Ranges is 2.5°C, mean summer temperature is 12°C and mean winter temperature is -7.5°C. Precipitation increases from east to west and also with elevation, from 600-800 millimetres (mm) per year. Valley regions are marked by warm, dry summers and mild, snowy winters, and subalpine areas have cool, showery summers and cold, snowy winters.
This region covers the Rocky Mountains of Alberta, incorporating the eastern flanks of the Continental Ranges. The major peaks cluster... More »
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